This invention concerns production of alkanolamines, especially diethanolamine in higher yields.
The production of alkanolamines is well known. Alkanolamines such as monoethanolamine ("MEA"), diethanolamine ("DEA") and triethanolamine ("TEA") are commonly made by reacting aqueous ammonia and an alkylene oxide such as ethylene oxide under suitable conditions to form the alkanolamine. This reaction generally produces a variety of alkanolamines. For example, reaction of aqueous ammonia and ethylene oxide typically produces a mixture of MEA, DEA, and TEA. It is well known that the relative amounts of MEA, DEA, and TEA produced are a function of the ammonia/ethylene oxide ratio. While it is known that the ammonia/ethylene oxide ratio can be adjusted to obtain 80-90 percent MEA or 80-90 percent TEA, the maximum amount of DEA in the mixture previously achievable is about 35 percent. Owing to its significant commercial utility, a process which increases the yield of DEA would be highly desirable.